We are almost done with our coop (thank you, Lord!) and am wondering if it should be vented. What we have is a 10x10 three sided building that will house both the chicken coop and duck house and small yards for each. The chicken coop is on the right side, in the upper half of the building. I'll have an egg door that opens from the outside wall and the door to their ramp and the yard that opens in the front. I also will have one section of the front that is hinged so we can open the whole thing and clean it. Two walls are insulated with the 3rd to be insulated before winter. The interior coop roof is not insulated but I'm thinking about insulating the bottom. There are not any windows. There will be 5 chickens in there at night only, or just during really, really crummy weather. So, should I vent it or not. The whole thing was built out of scrap lumber, so it's not super-tight anyway. And, our highest temps never exceed 80 degrees, and that's maybe only 1 or 2 days per year. We haven't seen over 60 all summer this year. The winters hang from between 10 above to 40 above. Same question applies to the duck house. It's construction is similar, just on the ground (on top of a pallet, actually) and squarer with no roost.